Project 2. Expansion of clinical research capacity at Kenema Government Hospital Lassa virus (LASV), a member of the family Arenaviridae, is the etiologic agent of Lassa fever (LF), a severe and often fatal hemorrhagic illness. It has been reported throughout West Africa from Guinea in the west to Nigeria in the east. Humans contract LASV primarily via direct or indirect contact with body fluids of rodents of the genus Mastomys, the natural reservoir. Nosocomial transmission can lead to large hospital outbreaks. The possibility of aerosol transmission and the lack of a vaccine have led to its classification as a BSL-4 and Category A Select Agent. Previous studies performed in the 1980's estimated up to 300,000 human LASV infections per year with 5,000 deaths per year. However, the natural history and mortality rate of disease remain poorly defined. Since these landmark studies were performed, significant advances have been made in LF clinical diagnostics as well as the laboratory capacity in endemic areas. Using newly developed Ag, IgG and IgM recombinant ELISAs (rELISA) and improved capacity at the site, we are now able to accurately study viremia and the immune response. This proposal will test the hypothesis: Development of IgM, but not a cellular inflammatory response, and decline in viremia during the early stages of symptomatic LF disease decreases mortality. Aim 1 is too identify clinical and virological determinants of Lassa fever outcome in a cohort of symptomatic Lassa fever patients presenting to Kenema Government Hospital. Previous studies have identified several clinical features and clinical laboratory parameters that predict a poor prognosis. However, no study has determined if degree of viremia correlates with clinical features or laboratory test abnormalities. We will test the hypothesis: Prolonged viremia correlates with disease progression and increased mortality. We will identify clinical and laboratory diagnostic and prognostic risk factors for LF and correlate them with viremia and risk of mortality. This aim will establish the natural history of LF disease and determine if the time course can be divided into distinct stages as previously suggested. Aim 2 is to identify biomarkers of infection and mortality. Recent development of rLASV IgM and IgG ELISAs as well as increased capacity at the KGH Lassa Fever Laboratory provide a unique opportunity to identify specific immune correlates with disease severity and risk of mortality. We will test the hypothesis: Delayed development of the humoral and an increased TH1 inflammatory immune response correlates with increased mortality. We will correlate specific humoral and cytokine profiles with disease progression and outcome. These studies are critical for the design of future interventional trials and the development of therapies for LF and other viral hemorrhagic fevers. Aim 3 will initiate Clinical trial capacity training. Over the past decade, a significant amount has been learned about the pathogenesis of LF and the human immune response. Trials are now needed to test existing and novel therapies for this disease. The objective of this aim is to build on previously funded capacity at the site and train critical team members in the essential elements needed to conduct clinical trials. This training is critical if the KGH site is to continue to contribute to our knowledge of and management strategies for VHFs.